Choosing Metals

Copper or Aluminum?

Both COPPER and ALUMINUM are approved by UL (Underwriters Laboratories) for the installation of Lightning Rod Systems. There is little argument that Copper is the material of choice because it is a better conductor of electricity. If aluminum is used in an installation, the cable has to be larger than the copper cable to conduct the same amount of current.

Whenever possible, we specify the use of Copper in our systems because it is the better material and is physically stronger and a better dollar value. The Copper cable is smaller and thus less conspicuous and blends in better with most architecture, such as against brick walls and dark roofs.

There are times when it is preferable to use Aluminum materials. Since Aluminum and Copper are of dis-similar metals, they tend to corrode each other. We would specify Aluminum in the following exceptions:

(1) If your roof were made of bare aluminum or bare galvanized steel.

(2) If your building were very light colored and the use of the dark copper cable would be unattractive.

(3) If the absolute lowest cost were the only consideration. NOTE: If you want to use copper anyway, you can use our “tinned” (lead coated) copper cable.

Aluminum Lightning Protection equipment is approved by Underwriters Laboratories and has proved most satisfactory, but there are a few precautions to consider when using this material:

1. Never use underground. The alkali in the soil will destroy aluminum. Aluminum should terminate at least 1′ above ground.

2. Aluminum and copper materials should not be used together unless approved bimetallic connectors are used.

3. Aluminum should never be used where it will come in contact with white wash, calcium, or alkali-base paint as these are most injurious to aluminum.

4. Aluminum should never be placed where leaves or moisture will collect and remain for a long period of time.

5. Copper grounding equipment is always used with aluminum systems.

Aluminum Grounding Detail:

Order #M3 Bimetal Splicer
You will need at least 5 feet of copper conductor cable for each ground rod location and make your transition from aluminum cable at least 1 foot above grade then change to copper and connect to your ground rod. Your ground rod must be at least 2 feet away from the building and the top of the ground rod must be buried 2 feet below grade REGARDLESS of length of ground rod. 8 foot ground rod is minimum so that means it has to go down 10 feet. A 10 foot ground rod needs to go down 12 feet. This is how you come up with at least 5 feet of copper. 2 feet away, 2 feet deep and 1 foot connected above grade.